Fault detection and location is indispensable for the protection and maintenance of transmission lines. Methods based on impedance estimation are generally used for this purpose. However, for power systems growing in size and complexity faster fault detection is essential for preserving transient stability. Traveling-wave based protection methods offer high-speed fault detection and accurate fault location. Nevertheless, there are some reliability issues that impede a widespread deployment of these techniques. In particular on the detection of faults occurring at zero-crossing voltage and faults in the relay proximity. In this paper a correlation function is employed for detecting disruptions in current and voltage sinusoidal waveforms. The correlation function is designed to detect any type of wave distortion, even those that are barely noticeable such as faults occurring at low-voltage magnitude.
